This invention relates generally to atomizing and spraying apparatus and, more particularly, to apparatus for atomizing liquid feed to a fluidized catalytic cracking riser reactor.
Apparatus of this general type is shown and described in detail in Dou et al. U.S. Pat. No. 5,306,418, the disclosure of which is incorporated herein by reference. In general, a liquid hydrocarbon feed is atomized by a gas such as steam and is discharged through a nozzle into the reactor. In the apparatus of the Dou et al patent, the preferred discharge nozzle has a generally hemispherical discharge end which is formed with a single elongated slot-like outlet orifice adapted to produce a flat fan-shaped spray.
A goal in atomizing and spraying apparatus is to achieve high efficiency. High efficiency in the context of the present apparatus refers to using as little steam energy as possible to break hydrocarbon feed of a given volume into particles having a large total surface area. Large surface areas are, of course, created by breaking the liquid into very fine particles. Heretofore, this has necessitated introducing the liquid hydrocarbon flow stream into the nozzle apparatus at relatively high pressure, such as on the order of 150 psi to 200 psi. This sometimes has required that the refinery use booster pumps and associated equipment in order to achieve the necessary pressurization of the liquid flow stream, which can be costly and add to the complexity of the spraying system.